At some point we're going to have to put a freeze on the number of checks that are included by default. The configurable nature of `pre-commit` is disappearing with everyone wanting their check to be included by default.

I can only imagine you wanted to remove the `rvm` check below for performance reasons. If not for performance I don't see why we would want to exclude `rvm` users. Adding more default checks also slows down startup time... =/

We can probably allow this one, but after this we'll have to have a hard cut off and take another pass at performance.